The legislation required that elevator doors remain open long enough for anyone who uses crutches, a cane or wheelchair to get on board, Ms. Penafiel said in an interview on Tuesday. “The riding public would not be able to make those doors close any faster,” she said.

The buttons can be operated by firefighters and maintenance workers who have the proper keys or codes.

No figures were available for the number of elevators still in operation with functioning door-close buttons. Given that the estimated useful life of an elevator is 25 years, it is likely that most elevators in service today have been modernized or refurbished, rendering the door-close buttons a thing of the past for riders, Ms. Penafiel said.

Take heart, though: The door-open buttons do work when you press them.

Crosswalk signals

New Yorkers (those who don’t jaywalk, that is) have for years dutifully followed the instructions on the metal signs affixed to crosswalk poles:

To Cross Street

Push Button

Wait for Walk Signal

But as The New York Times reported in 2004, the city deactivated most of the pedestrian buttons long ago with the emergence of computer-controlled traffic signals. More than 2,500 of the 3,250 walk buttons that were in place at the time existed as mechanical placebos. Today there are 120 working signals, the city said.

About 500 were removed during major construction projects. But it was estimated that it would cost $1 million to dismantle the nonfunctioning mechanisms, so city officials decided to keep them in place.

Most of the buttons were scattered throughout the city, mainly outside of Manhattan. They were relics of the 1970s, before computers began choreographing traffic signal patterns on major arteries.

ABC News reported in 2010 that it found only one functioning crosswalk button in a survey of signals in Austin, Tex.; Gainesville, Fla.; and Syracuse.

Office thermostats

The same problem that confronts couples at home — one person’s perception that a room is too cold is another’s that it is too warm — faces office workers as well.

Depending on where you work, you might find the thermostat in a plastic case under lock and key, but if you’re lucky you might have control over one.

One respondent, David Trimble of Fort Collins, Colo., wrote The News that people “felt better” that they could control the temperature in their work space after a nonfunctioning thermostat was installed. “This cut down the number of service calls by over 75 percent,” he wrote.

Sense of control

Though these buttons may not function, they do serve a function for our mental health, Ellen J. Langer, a psychology professor at Harvard University who has studied the illusion of control, said in an email.

“Perceived control is very important,” she said. “It diminishes stress and promotes well being.”

John Kounios, a psychology professor at Drexel University in Philadelphia, said in an email there was no harm in the “white lie” that these buttons present. Referring to the door-close button on an elevator, he said, “A perceived lack of control is associated with depression, so perhaps this is mildly therapeutic.”

Knowing that pushing these buttons is futile does not mean it will stop people from trying, he added. The reward of the elevator door closing always occurs eventually, he said.

“If the door never closed, we would stop pressing the button,” he continued. “But in that case, of course, we would stop using the elevator altogether. So, that habit is here to stay. Similarly, even though I have grave doubts about the traffic light buttons, I always press them. After all, I’ve got nothing else to do while waiting. So why not press the button on the off chance that this one will work?”